Re: [R] matrix not working

From: David Winsemius <dwinsemius_at_comcast.net>
Date: Thu, 26 May 2011 14:58:22 -0400

On May 26, 2011, at 1:53 PM, Andy Zhu wrote:

> Dat:
>
> 1. you can use as.matrix to convert data.frame to matrix;
> 2. it is likely that the internal representation of your data.frame
> may not be numerical value; matrix can only take on numeric.
>

Not true. Can be any single mode, including "character", "list", and "logical".

-- 
david.


>
>
> --- On Thu, 5/26/11, Dat Mai <dat.d.mai@gmail.com> wrote:
>
> From: Dat Mai <dat.d.mai_at_gmail.com>
> Subject: [R] matrix not working
> To: r-help_at_r-project.org
> Date: Thursday, May 26, 2011, 12:24 PM
>
> Hello All,
>
> I'm trying to create a matrix from a dataframe (let's call it df):
> ......a......b.....c.....d
> a inputs output
> b inputs output
> c inputs output
> d inputs output
> e inputs output
>
> The inputs are represented by columns a and b
> The outputs are represented by columns c and d, but the only outputs
> are
> those from column d
> - some values from column d are NA
> - column d was created with the code:
>
> df$d=rank(df$c, na.last="keep")
>
> #----------R Code---------#
> item=unique(df$a)
> n=length(list)
>
> r=matrix(data=NA,nrow=n, ncol=n, dimnames=list(PRR1=item, PRR2=item))
>
> for(j in 2:ln)
> {
> for(i in 1:(j-1))
> {
> input1=rownames(r)[i]
> input2=colnames(r)[j]
>
> q=df[(df$a==input1 & df$b==input2), "d"]
>
> if(length(q)==0)
> {
> q=df[(df$a==input2 & df$b==input1), "d"]
> }
>
> if(length(q)==0)
> {
> q=NA
> }
>
> r[j,i]=q
> r[i,j]=q
> r[j,j]=q
> }
> }
>
> The result is a matrix with the appropriate dimensions, but
> everything is
> filled with NA instead of the rankings of the various combinations.
> I'd like
> for the matrix to be filled with the ranking values--what have I
> done wrong?
> --
> Best,
> Dat Mai
> PhD Rotation Student
> Albert Einstein College of Medicine
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD West Hartford, CT ______________________________________________ R-help_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Received on Thu 26 May 2011 - 19:08:11 GMT

This quarter's messages: by month, or sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

All messages

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 26 May 2011 - 20:10:10 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive